Piston



Nov. 10, 1925 w. E. JOHN PISTON Filed April 15, 1922 Patented Nov.10,1925.

A'l'ES WILLIAM'E. JOHN, OF DAYTON, OH IO, ASSIGNGB TO GENERAL MOTORSRESEARliH REOBATION, 0F DAYTON, QHIO, A CORPORATION OF DELAWARE.

PIS'EQN.

Application filed April 15, 192%. Serial No. 5,108.

To all whom it 71mg concern:

Be it known that l, WILLIAM E. JOHN, a citizen of the United States ofAmerica, residing at Dayton, county of Montgomery, and State oi @hio,have invented certain new and. useful Improvements in Pistons, ofwhich'the following is a full, clear, and exact description.

This invention relates to pistons for internal combustion engines andhas particular reference to. cooling means therefor. I

As is well known, a great problem in piston design is the provision ofmeans to keep the piston cool enough to guarantee the proper operationthereof when the engine is working hard. Some of the diliicultiesencountered are the excessive expansion' of the piston making itnecessary to provide more clearance between the piston and cylinderwalls; the excessive heating up of the central port of the top of thepiston thereby reducing the compression which can be solely used withoutpreiition end reducing the volumetric efliciency of the engine cylinder,and the dificulties of properly lubricating the piston. ..Also the hightemperature of the central part or the top of the piston necessitatesas? greater thic'zlr-v ness for strength considerations and thereforeadds to the weight of the iston which for bolance considerations shou dbe as light no possible.

Among the objects of the present invention is to enable it considerabledecreese in weight oil cast iron pistons, at the some time providing fora heat conducting capacity equal to or greater than that oi thiclr sections commonly used.

in the drawing:

l is vertical section through the piston.

Fig. 2 is it view of the motel insert of high hoot conductivity which iscost in the piston, the left hell of the insert being shown in section.

Fig; 3 is or plan. view of the motel insert.

Sinnilnr reference charncters refer shin-- lnr ports thron #hout theseveral views.

Numeral id esignetes the metal insert, which is preierebly mode of sheetcopper and of snhstentinll the same dimensions es the piston whici is-tobe cost nronnd reasons. This insert 10 is set in the mold and the piston15 cast about it in a manner which will he reedily understood by thoseskilled in the art. Preferably the insert 10 is provided with aplurality of small holes 11 having the metal turned in or out to formshort flanges 12 around the holes. These flanges l2 aid in carryingtheheat to the inner surface olthe piston where the heat is dissipatedto the air and oil in the crank case of the engine. The top of thepiston-may also have similar flanges 13 en tending upwardly, as shown,to aid in conducting the heat from-the upper surface of the piston downto the 00 per insert, The flanges 12 and 13 prefers. ly extend to thesurface of the cast metal, but if desired they may extend only to apoint just below the surface of the cast metal.

The piston is preferably cast of cast iron.

on account of its coeflicient of expansion being the same as that ofthee linder. wells, aring qual- 1ties,'but of. course the scope of theinven-' and because of its satisfactory tion includes the .use of othercast motels being used. The copper insert 10 greatly increases the heatconductivity over a sirni- 1 larpiston without the insert and hence thepiston will run much cooler and all the attending advantages obtained.If desired,

the copper insertmay not extend the'lnlles the greetest u lid tendencyto heat to the side walls of the piston. Gt course in any of the shovedcscribed modificotions any motel of gh heat conductivity mey he usedfor the inserts instead of copper.

While the form of mechanism herein shown and described constitutes epreferred form of embodiment of the present invention, it is to heunderstood that other forms might be adopted, ell coming within -thescope of the clnims which follow.

Whnt l eleim is es follows: l. A cast metal piston havi embedded withinits heed a continuous insert of motel extending throughout seid heed endot' illlil llll higher heat conductivity than said cast metal. v

2. A cast metal piston havin cast within its Walls an insert of metal 0higher heat conductivity than said cast metal, said in sert havingportions extending to the surface of the piston walls.

3. A cast metal piston having embedded within its head and skirtportions a continuous sheet metal insert of higher heat conductivitythan said cast metal.

4. A cast metal piston having cast within its walls a sheet metal insertof higher heat conductivity than said cast metal, said insert havingportions extending to the surface of said'cast metal.

5. A cast metal piston having cast within its walls a' continuous sheetmetal on shaped insert of the general form of tile piston andhaving-higher heat conductivity than said cast metal.

In testimony whereof I hereto afiix my signature.

WILLIAM E. JOHN.

